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Maladaptive movement behavior is a leading cause of failure for reptile reintroductions, thus characterizing movement for translocated populations is important to project success. From 2014–2016 we radio‐tracked 183 immature reintroduced alligator snapping turtles (Macrochelys temminckii) using very high frequency telemetry in a stream in southern Illinois, USA. We assessed environmental, temporal, morphometric, and microhabitat factors influencing movement, including post‐release dispersal from reintroduction sites, movement probability, and step length. We used directional statistics to investigate the effects of precipitation and age on directional movement in the stream. Numerous factors influenced active movement, including ambient temperatures, time since release, use of log jams, turtle size, and age. Precipitation had an age‐biased effect on movement. Directional analyses suggested that movement was largely passive as turtles were swept downstream with increased discharge. Overall, the behavior of reintroduced alligator snapping turtles was similar to that reported in wild populations. Passive downstream transport has implications for reintroduced and natural populations as a force for unintentional emigration in channelized streams under current conditions and future high flow regimes. [ABSTRACT FROM AUTHOR]

Abstract Environmental DNA (eDNA) analysis is an effective and non‐invasive technique for surveying and monitoring rare, threatened, or endangered (RTE) species. Compared to conventional capture‐based sampling, eDNA analysis may offer a more cost‐effective approach for surveying RTE species, yet few studies have compared their cost‐efficiency—a critical consideration for conservation planning. We compared the costs, effort, and relative performance of aquatic eDNA sampling and conventional trapping for detecting the Alligator Snapping Turtle, Macrochelys temminckii Troost, 1835, in southwest Louisiana, United States. Environmental DNA was sampled quarterly over 1 year (2018–2019) at 19 streams, including three streams where M. temminckii presence had been previously confirmed via conventional trapping efforts (2012–2013). Water samples from each stream were analyzed using quantitative polymerase chain reaction (qPCR) to assess M. temminckii eDNA presence/absence. Time and costs (i.e., labor, travel, wages, and supplies) per detection via eDNA analysis and trapping were calculated and compared. Environmental DNA analysis documented the presence of M. temminckii DNA at two of the three streams where individuals had previously been trapped and yielded detections (qPCR amplifications) at 16 additional streams not previously sampled, expanding M. temminckii's documented distribution at our study sites by 84%. Environmental DNA analysis returned a detection rate (per site) 5.55 times higher than conventional trapping and was 18.7% less expensive. Our results provide evidence that strategically deployed eDNA surveys may be an effective and cost‐efficient approach for detecting freshwater RTE species. With eDNA analysis, additional resources can be invested toward expanding survey coverage and increasing sampling frequency, allowing managers to more effectively target subsequent intensive monitoring efforts.

The alligator snapping turtle (Macrochelys temminckii) is the largest freshwater turtle species in North America and is classified as state endangered in Illinois. Head start programs that include health assessments and pathogen detection are being conducted to restore this species to its historic range. Physical examinations and oral and cloacal swabs were collected from 97 head start alligator snapping turtles prerelease and from 58 recaptured turtles postrelease in 2014. Conventional polymerase chain reaction and sequencing targeting the RNA polymerase beta subunit gene and the 16S-23S ribosomal RNA intergenic spacer detected a single prerelease individual with Mycoplasma sp. with closest relation to Mycoplasma spp. of other freshwater turtles. This individual did not display any clinical signs at the time of release or sampling. Mycoplasmosis has been characterized as a disease of conservation concern in tortoises and may represent a threat to small and fragmented chelonian populations. Findings of this study indicate that Mycoplasma sp. DNA is present in an Illinois alligator snapping turtle, and future investigation into the impact of this infection may support conservation efforts. [ABSTRACT FROM AUTHOR]

Few studies have characterized the prevalence of intraerythrocytic parasites in free-ranging chelonian populations or their occurrence across habitats. It is hypothesized that chelonians in different habitats have different exposures to vectors and thus differences in hemoparasite presence. This study explored the prevalence and intensity of intraerythrocytic parasites by examining blood smears from four species of Illinois turtles: wild Blanding's turtle (Emydoidea blandingii), eastern box turtle (Terrapene carolina carolina), ornate box turtle (Terrapene ornata ornata), and prerelease head-started alligator snapping turtle (Macrochelys temminckii). Intraerythrocytic parasites were identified in all examined species except for the alligator snapping turtle. For all age classes, Blanding's turtles had both the highest prevalence of hemoparasites and the highest intensity of infection of all sampled species, whereas adult Blanding's turtles had a significantly higher prevalence than juveniles (P < 0.05). Because this is the first study of hemoparasites in Illinois chelonians, further research is needed to identify the specific species of intraerythrocytic parasite, the potential vectors, and the effect that these hemoparasites have on the health of chelonians. [ABSTRACT FROM AUTHOR]

Herpesviruses are significant pathogens of captive-reared and free-ranging chelonians worldwide. Lesions associated with chelonian herpesvirus infection are species dependent and include stomatitis in tortoises, hepatic necrosis in pond turtles, and fibropapillomas in sea turtles, among other conditions. Herpesviruses also have been detected in several free-ranging freshwater turtle species with no clinical signs of illness at a prevalence from 2 to 56%. The alligator snapping turtle (Macrochelys temminckii) is a freshwater turtle species endemic to the United States that has experienced declines throughout its range. Reintroduction of this species is currently underway in several states. As part of a health surveillance program, in concert with reintroduction efforts, we investigated the presence of herpesvirus in captive and free-ranging alligator snapping turtles. Using conventional consensus polymerase chain reaction, we tested combined oral/cloacal swab DNA samples (n = 197) from head-started alligator snapping turtles prerelease and postrelease in southern Illinois (n = 153), prerelease samples from adult turtles confiscated from Florida (n = 18), and prerelease samples from captive-reared individuals from northern Louisiana (n = 26). Herpesvirus DNA was not detected in any sample. Possible explanations for these results include lack of exposure, latency in tissues not sampled, and viral quantities below the level of detection of the assay. Continued surveillance for this and other pathogens is helpful in characterizing potential disease risks from captive-reared reintroduction programs and will enhance future conservation efforts of this species. [ABSTRACT FROM AUTHOR]

The alligator snapping turtle Macrochelys temminckii is the largest freshwater turtle in North America and humans seek it as a food source, primarily in Louisiana. Scientists point to decades of intensive commercial harvest of alligator snapping turtles as a cause of population declines. The Louisiana Department of Wildlife and Fisheries initiated a head-start program for alligator snapping turtles and released 53 head-started juveniles at seven sites along an approximately 5.7-km stretch of Bundick Creek in southwest Louisiana between November 2015 and October 2016. Before release, department personnel measured, weighed, and marked all alligator snapping turtles with both an internal passive integrated transponder tag and a numbered external tag. In 2018, the U.S. Geological Survey initiated a turtle trapping survey at those seven release sites targeting the head-started alligator snapping turtles. In 1 wk of trapping effort at each site, we recorded 69 turtle captures comprising seven species, including 15 alligator snapping turtles (representing 12 individuals). Of those 12 individuals, 8 were head-started juveniles and 4 were native to the creek. A landowner captured an additional head-started juvenile alligator snapping turtle during our trapping and we took measurements before its release. A minimum of 17% of head-started alligator snapping turtles survived since release, and we trapped most captured head-started individuals near their release site; the captured individuals exhibited growth consistent with other studies, indicating acclimatization to their new environment. Three head-started alligator snapping turtles had their external tags entangled in the net mesh, and two of these turtles drowned. An additional two head-started individuals lost their external tags in the natural environment prior to their capture in this study. The Louisiana Department of Wildlife and Fisheries discontinued the use of external tags based on our findings, as these tags were detrimental to the health of head-started turtles. [ABSTRACT FROM AUTHOR]

High harvest rates during the 1900s led to declines of Macrochelys temminckii (Alligator Snapping Turtle) throughout much of its range. Recent research to determine the status of Alligator Snapping Turtles has been completed in some regions of Louisiana, but information is lacking for the southwestern region of the state. To determine the distribution and abundance of Alligator Snapping Turtles in southwestern Louisiana, we conducted trapping efforts in the lower Calcasieu, Mermentau, and lower Sabine river systems from March 2012 through October 2013 using baited hoop nets. In 731 trap nights, we captured 14 individuals (2 M, 4 F, 8 Juv) in the Mermentau and Calcasieu river systems. Our trapping efforts did not detect Alligator Snapping Turtles at Sabine River sites, although one individual was found dead on a fishing hook of a hanging limb line. Our catch per unit effort (CPUE) was 0.021 across the 3 river drainages. Population levels appear to be smaller than observed elsewhere in Louisiana and in neighboring southern states. We recommend that future surveys be conducted to determine population trajectories and that a system be implemented for monitoring commercial fishing bycatch and recrea tional harvest. [ABSTRACT FROM AUTHOR]

The alligator snapping turtle (Macrochelys temminckii) is under consideration for listing as a federally endangered species. Distributional data and estimates of population sizes are needed to make a sound decision regarding listing, but this information is largely unavailable due to the immense effort required for M. temminckii trapping surveys. To alleviate difficulty in detection and to help inform subsequent field-intensive survey efforts, we developed an environmental DNA (eDNA) method capable of providing presence data even in systems with high turbidity and suspended organic material. The assay we developed utilizes probe-based quantitative polymerase chain reaction and reliably amplifies M. temminckii eDNA in both lentic and lotic systems, with no amplification observed in other nontarget, sympatric turtle species. The novel eDNA method developed, optimized, and field-tested in this study provides a promising tool for detection of alligator snapping turtles, with resultant presence data likely to prove beneficial for the management and conservation of this species. [ABSTRACT FROM AUTHOR]

The interpretation of plasma biochemical profiles can be confounded by the methodologies by which samples are analyzed. The goal of this study was to compare agreement between two biochemical analyzers for plasma samples from alligator snapping turtles (Macrochelys temminckii). Blood was obtained from the dorsal coccygeal vein of captive-reared, juvenile turtles (n = 34), stored in lithium heparin tubes, and centrifuged to separate plasma from whole blood. Plasma samples were stored at 5°C prior to and in between analyses on VetScan (VetScan2, Abaxis, Union City, CA 94587, USA) and Olympus (Olympus AU640, Beckman Coulter, Brea, CA 92821, USA) analyzers within 2 hr of each other. Agreement between the VetScan and Olympus analyzers was investigated using Passing-Bablok regression analysis for aspartate aminotransferase, creatine kinase, glucose, calcium, phosphorus, total protein, albumin, globulin, potassium, and sodium. Agreement between the two analyzers was outside of acceptance limits and outside of clinical allowable error limits for all analytes as established by the American Society for Veterinary Clinical Pathology. The results of biochemical analyses of alligator snapping turtle plasma cannot be compared between VetScan and Olympus analyzers in a clinical setting. Comparison of biochemical analyses within analyzer units, however, may still be clinically useful. Future studies are warranted to investigate the precision of each analyzer for alligator snapping turtle plasma. [ABSTRACT FROM AUTHOR]

A severely underweight alligator snapping turtle Macrochelys temminckii Troost in Harlan, 1835, was found near Tyler, Texas, and taken to the Caldwell Zoo. Blood films were submitted to Texas A&M University, College Station, Texas, for morphological and molecular identification of haemogregarine-like inclusions in the red blood cells. Intraerythrocytic Haemogregarina sp. forms were found on microscopic examination at a parasitemia of <1 %. The morphology and morphometric data for the forms indicate similarity to Haemogregarina macrochelysi n. sp. Telford et al., 2009, previously reported in alligator snapping turtles in Florida and Georgia, but two characteristic stage forms were not shared between H. macrochelysi n. sp. and the parasite found in this report. The haemogregarine 18S ribosomal RNA gene (1555-bp fragment) was amplified and cloned, and five clones sequenced. The sequences were deposited in the NCBI GenBank database. All five showed ∼96 % identity to Haemogregarina balli Paterson and Desser, 1976, Hepatozoon sp., and Hemolivia stellata Petit et al., 1990. A 774-bp segment shared 98-99 % identity with the corresponding Haemogregarina sp. rDNA sequence (KR006985) from Caspian turtles ( Mauremys caspica McDowell, 1964) in Iran. A neighbor-joining phylogenetic tree generated from aligned sequences from the clones, 26 hematozoa, Adelina dimidiata Schneider, 1875, and Cryptosporidium serpentis Levine, 1980, revealed the cloned sequences clustered on their own branch within the Haemogregarina spp. clade. No genetic data are available for H. macrochelysi n. sp. at this time, so it remains unclear if this parasite in a Texas alligator snapping turtle is conspecific with H. macrochelysi n. sp. [ABSTRACT FROM AUTHOR]

Macrochelys temminckii (Alligator Snapping Turtle) was petitioned for federal listing as threatened under the Endangered Species Act in 2012 as a result of population declines attributable in part to harvest for human consumption. The species was listed as threatened in 1992 in Georgia, where all harvest of the species was closed. Because little is known about how Alligator Snapping Turtle populations respond to protection, we surveyed Georgia's Flint River, which had originally been surveyed in 1989, to assess whether abundance of Alligator Snapping Turtles increased following close of commercial harvest. Our survey, conducted in 2014 and 2015 yielded captures of 52 Alligator Snapping Turtles with an overall catch per unit effort (CPUE) of 0.09 turtles/trap-night, as compared to 62 captures and a CPUE of 0.08 turtles/trap-night in the 1989 survey. Although CPUE was similar between the two studies, we observed differences among the lower, middle, and upper reaches of the river; CPUE increased in the lower reach, decreased slightly in the middle reach, and remained the same in the upper reach of the Flint River. Mean size (carapace length) of Alligator Snapping Turtles did not differ between the 2 surveys, but in 2014-2015 we caught nearly twice as many immature (<40 cm carapace length) turtles as adult males and females, and the highest proportion of immature turtles was captured in the upper reach. Our findings suggest that the Alligator Snapping Turtle population in the Flint River has not increased despite 22 years of protection from commercial harvest. Recovery may be hampered by life-history characteristics of the species including delayed maturity and low reproductive output; however, we cannot rule out possible ongoing mortality of Alligator Snapping Turtles from illegal harvest or drowning on abandoned limb lines, as has been observed in other populations. [ABSTRACT FROM AUTHOR]

The nests of embryonic turtles naturally experience elevated CO2 (hypercarbia), which leads to increased blood ... and a respiratory acidosis, resulting in reduced blood pH [extracellular pH (pHe)]. Some fishes preferentially regulate tissue pH [intracellular pH (pHi)] against changes in pHe; this has been proposed to be associated with exceptional CO2 tolerance and has never been identified in amniotes. As embryonic turtles may be CO2 tolerant based on nesting strategy, we hypothesized that they preferentially regulate pHi, conferring tolerance to severe acute acid--base challenges. This hypothesis was tested by investigating pH regulation in common snapping turtles (Chelydra serpentina) reared in normoxia then exposed to hypercarbia (13 kPa ...) for 1 h at three developmental ages: 70%and 90%of incubation, and yearlings. Hypercarbia reduced pHe but not pHi, at all developmental ages. At 70% of incubation, pHe was depressed by 0.324 pH units while pHi of brain, white muscle and lung increased; heart, liver and kidney pHi remained unchanged. At 90% of incubation, pHe was depressed by 0.352 pH units but heart pHi increased with no change in pHi of other tissues. Yearlings exhibited a pHe reduction of 0.235 pH units but had no changes in pHi of any tissues. The results indicate common snapping turtles preferentially regulate pHi during development, but the degree of response is reduced throughout development. This is the first time preferential pHi regulation has been identified in an amniote. These findings may provide insight into the evolution of acid--base homeostasis during development of amniotes, and vertebrates in general. [ABSTRACT FROM AUTHOR]

Legend states that the alligator snapping turtle (Macrochelys temminckii) should be handled with extreme caution as it has jaw strength powerful enough to bite a wooden broomstick in half. Tales of bite injuries from what is the largest freshwater turtle in North America exist anecdotally, yet there are few descriptions of medical encounters for such. The risk of infection from reptilian bites to the hand in an aquatic environment warrants thorough antibiotic treatment in conjunction with hand surgery consultation. We present the first case report of a near total amputation of an index finger in an adolescent boy who had been bitten by a wild "gator snapper." [ABSTRACT FROM AUTHOR]

The conservation of large, long-lived turtle species can be a challenging issue because their life-history strategies make populations sensitive to changes in adult survivorship and populations may be difficult to sample. The Alligator Snapping Turtle ( Macrochelys temminckii) is a large freshwater turtle species occurring in North America for which commercial harvest has severely reduced populations throughout the species range. Given recent population declines and a general deficit of demographic knowledge for Macrochelys, we conducted a mark-recapture study of M. temminckii from 1997-2013 in Spring Creek, Georgia, USA. We made 166 captures of 75 individuals using baited hoop-net traps and skin-diving searches. The observed and estimated population structure described the adult sex ratio as even and adults as more abundant than juveniles. Apparent survival was higher for adult males (0.98) and females (0.95) than for juveniles (0.86), and we estimated a population density of 13-14 turtles/stream kilometer. The survival estimates for adult M. temminckii are among the highest of all freshwater turtle species reported in the literature. We used the empirical demographic parameters described here and a literature review to build an updated population model for M. temminckii; the model estimated a finite rate of population increase consistent with a growing population (λ = 1.036) at Spring Creek, and population viability analysis found the population growing over the next 50 yr in 100% of simulations. Application of our model to published survival estimates from two impacted western populations indicated a declining population (λ = 0.563) with a high risk of extirpation in Oklahoma and a population with a slow rate of decline (λ = 0.978) but approaching stability in Arkansas. Simulations identified combinations of survival values which generate viable populations and also characterized population structure resulting from viable scenarios. This is the first study to document a stable and viable population of Macrochelys. We suggest that the population parameters described at Spring Creek are the best approximation of reference demographic conditions for Macrochelys to date, and this study provides a general framework applicable for large, long-lived, endangered turtle species for which demographic data are unavailable. [ABSTRACT FROM AUTHOR]

Urbanization and the continued encroachment of human activity into green spaces often result in the decline of several animal species. Macroclemys temminckii (alligator snapping turtle) is particularly sensitive to human activity as it is an opportunistic scavenger and carnivore. The longevity of this species, as well as its dietary habits make it an excellent candidate for biomonitoring. In this preliminary study, twelve (12) shell samples were collected from individuals trapped at Fort Polk, LA and Sam Houston Jones State Park, LA. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to determine the presence of the toxic metals cadmium (Cd), chromium (Cr) and lead (Pb) in addition to other trace minerals and iron (Fe). The levels of the toxic metal were below the detection limit of the ICP-OES. This report represents the first study of this nature on Macroclemys temminckii . [ABSTRACT FROM AUTHOR]

Macrochelys suwanniensis is a newly described species endemic to the Suwannee River drainage in the southeastern United States. We conducted a study of M. suwanniensis in the Santa Fe River (SFR), the major Florida tributary of the Suwannee River, between 2004 and 2011. We captured 109 individuals (24% immature, 44% adult female, 32% adult male). Adult males (mean straight midline carapace length [CL] = 530.7 mm, mean mass = 34.0 kg) were significantly larger than adult females (mean CL = 424.0 mm, mean mass = 17.2 kg), with a sexual size dimorphism index of −0.25 based on mean CL. The largest turtle in our study was 623 mm CL and weighed 54.4 kg. Adult females were significantly larger (CL) in the lower SFR than in the upper SFR (these reaches are separated where the river flows underground for 5 km). All adult males > 600 mm CL were captured in the lower SFR. Adult females were proportionately heavier in the upper SFR than in the lower SFR; males did not show this difference. We hypothesize that these differences in body size are related to habitat. The M. suwanniensis population in the SFR presently appears healthy, but we suggest this species requires continued protection because of vulnerability of adults to harvest. [ABSTRACT FROM AUTHOR]

Reintroduction is a common management tool for conserving imperiled species, but many reintroductions have included little or no postrelease assessment of project success. The alligator snapping turtle ( Macrochelys temminckii) is a long-lived species that has experienced significant declines throughout its range, although suitable habitat remains. We report the findings of a reintroduction effort that was initiated in 2008 near the northwestern limit of the species' range. Two hundred forty-six M. temminckii were released into the Caney River and its tributary, Pond Creek, from 2008 to 2010. All turtles exhibited measurable growth by their first recapture 1-3 yrs after release, and no decline in body condition was observed, either in comparison to prerelease body condition or to the condition of animals in the same cohorts that remained in captivity. Apparent survival and recapture probabilities increased with age. Apparent survivorship values were higher for turtles released in the main channel of the Caney River, but recapture probabilities were higher in its tributary. Ultimately, survivorship values may have been influenced by low recapture rates and emigration, in addition to mortality. [ABSTRACT FROM AUTHOR]

Recent interest in diagnoses and relationships between lineages of the alligator snapping turtle ( Macrochelys temminckii) present conflicting patterns of molecular variation across the taxon's range. This study uses geometric morphometric techniques to test molecular hypotheses. We analyse alligator snapping turtle cranial variation amongst populations (i.e. drainages) with the hypothesis that populations of turtles recovered as monophyletic by previous molecular studies are more similar to each other in cranial shape. Dorsal, lateral and ventral cranial shape analyses corroborate the uniqueness of populations recovered by molecular genetic hypotheses. Additionally, analyses reveal near equal separation between drainages that were assigned to monophyletic clades by previous phylogenetic studies. These results reveal the potential for more independent lineages that have yet to be diagnosed, and unique cranial shapes are described for our three most heavily sampled drainages. [ABSTRACT FROM AUTHOR]

The article estimate the clutch size using eggshell fragments in depredated turtle Macrochelys temminckii nests. Topics discussed include counting the number of egg shells found in and around the nest cavity; greater size of individual eggs rather than after the shells were decalcified in acid; evaluation of accuracy of number of nests shell fragments and shell membranes and applicability of eggshell fragments methods in egg laying amniotes with high predation rates.

We evaluated nest-site selection in a reintroduced population of Macrochelys temminckii at two locations in southeastern Oklahoma by comparing mean values of variables characterizing microhabitat at nest-sites and random sites. We also analyzed the spatial distribution of nests using a computer randomization procedure. The spatial distribution of nests did not differ significantly from random. However, females nested in areas with significantly greater water depths 2 m from the shoreline and significantly less ground cover compared to random sites. Areas with little ground cover might indicate sites with thermal characteristics appropriate for incubation of eggs laid by M. temminckii, and greater water depth may provide cover for females prior to nesting. The discovery of nest-sites at the same location in consecutive years suggests that some female M. temminckii might return to the same place to nest repeatedly, but further study is required to confirm whether this species exhibits nest-site fidelity. [ABSTRACT FROM AUTHOR]

Kentucky falls within the northern periphery of the range of Macrochelys temminckii (Alligator Snapping Turtle). To better understand the status and distribution of this species, we conducted a multi-year survey targeting areas with historical records and other suitable habitat in western Kentucky. A secondary goal of this study was to collect baseline freshwater turtle-distribution data from western Kentucky. Survey efforts from 30 May 2003 through 17 May 2012 resulted in no Alligator Snapping Turtle captures. Total survey effort comprised 829 net nights over 118 survey nights at 24 sites within 10 Kentucky counties. The average number of survey nights per site was 4.9, and the average number of net nights per site was 34.5. Despite survey efforts comparable to other studies, it is possible that Alligator Snapping Turtles remain in suitable habitats in Kentucky at densities that were too low to detect with our survey methods. If continued intensive outreach and sampling in Kentucky fail to detect this species, the reintroduction of captive-propagated individuals should be considered in suitable habitat. [ABSTRACT FROM AUTHOR]

We introduced 250 alligator snapping turtles (Macrochelys temminckii) originating from a turtle farm in Arkansas into six pools adjacent to the Washita River in Johnston, Bryan, and Marshall counties, Oklahoma. Additionally, we released 16 captive-bred and reared juvenile turtles. We used radiotelemetry and mark-recapture to monitor dispersal of turtles, selection of microhabitat, and patterns of movement. We placed transmitters on 16 adult turtles from Arkansas and 16 captive-bred juveniles 2-4 years old. We recorded 198 locations of 32 individuals by radiotelemetry between May 2007 and August 2008. We recaptured 45 turtles one-five times using hoop nets employed for 501 trap-nights. We compared movement and selection of habitat between sexes and age classes for the parameters water depth, bottom temperature, turbidity, and canopy cover. Adults and juveniles chose shallower depths with more canopy than available randomly. Additionally, adults chose greater depths than did juveniles, and juveniles chose areas with more canopy than did adults. There was no difference in selection of habitat between sexes. Adults utilized a larger linear home range than did juveniles. [ABSTRACT FROM AUTHOR]

Abstract: The alligator snapping turtle, Macrochelys temminckii, exhibits type II temperature-dependent sex determination (TSD), wherein females are produced at high and low incubation temperatures. This TSD pattern is well studied at constant temperatures, but little work has focused on sex ratios in natural nests that experience daily and seasonal temperature fluctuations. We monitored nesting activity of reintroduced Macrochelys temminckii at Tishomingo National Wildlife Refuge in 2010–2011. Nests located prior to predation were excavated to determine clutch size and the eggs were reburied with a temperature data logger to collect nest temperatures. Overall, 24% of nests were protected with wire mesh prior to predation, and the average clutch size in intact nests was 22.4 eggs. Nest predation rates in the study population will likely approach 100% if nest protection efforts do not continue. Temperature profiles were used to compare estimated sex ratios using two methods—mean nest temperature during middle third of incubation and the degree-day model—to actual sex ratios in naturally incubated Macrochelys temminckii nests. The sex ratio in all 2010 recruits was female-biased (91.8% female); 2011 nests did not produce any hatchlings, likely the result of severe drought. The predicted sex ratios based on mean nest temperature and the degree-day model matched actual sex ratios in the warmer nests (0% male), but the degree-day model estimate proved more accurate in the cooler nest. A strongly skewed population sex ratio could become a threat to this reintroduced population if the strongly female-biased sex ratio in 2010 reflects a long-term trend. [Copyright &y& Elsevier]

Historic commercial collecting of the alligator snapping turtle (Macrochelys temminckii) appears to have severely reduced populations throughout much of its range. In this study, we analyze 8 seasons of turtle-trapping data from 11 major rivers in southern Alabama and provide the first report on the status of the species in the state. During 1332 trap nights, we captured 93 M. temminckii in 7 rivers in south Alabama. We recorded relatively low overall catch per unit effort (CPUE; 0.062 using paired hoop nets connected by a lead net, 0.081 using single-baited hoop nets) compared with recent studies from other states. By evaluating relative abundances, size distributions, and sex ratios, we document variation in abundance among independent river populations as well as unexpected sex ratios. In particular, the Fowl River population is characterized by unexpectedly high abundance (0.478 CPUE) and may represent historic population conditions prior to commercial trapping. We discuss distribution and abundances, conservation concerns, and the significance of the Fowl River with respect to the recovery of populations throughout the species' range. This study contributes baseline population data to better understand the ecology and conservation of M. temminckii both in Alabama and across its entire range. [ABSTRACT FROM AUTHOR]

Feeding preference of Macrochelys temminckii (Alligator Snapping Turtle) is not well known. Juveniles reared with no prior exposure to natural prey were tested for innate prey (i.e., fish) preference and foraging ability for mussels in coarse and fine substrates. Alligator Snapping Turtles consumed fish non-selectively, except that they selected Lepomis macrochirus (Bluegill) over Gambusia affinis (Mosquitofish) in live-prey trials, and Lepomis cyanellus (Green Sunfish) over Notemigonus crysoleucas (Golden Shiners) in carrion trials. Juvenile Alligator Snapping Turtles were less active and less successful when foraging for a benthic prey species, Lampsilis siliquoidea (Fatmucket), in coarse substrate than they were when the mussels were in fine and no substrates. Juvenile Alligator Snapping Turtle preference for Bluegill in a controlled environment corresponds to predator and prey habitat associations but could also be influenced by prey (i.e., fish) behavior. Likewise, enhanced activity and prey encounters in fine substrate are consistent with observations of Alligator Snapping Turtle habitat use. [ABSTRACT FROM AUTHOR]

Nest depredation is a major source of mortality in many turtle populations. Although turtle life histories may have evolved with relatively high levels of nest depredation, present-day levels may be negatively impacting populations that are already declining. This degree of depredation may be problematic for species such as Macrochelys temminckii (Alligator Snapping Turtle), which has relatively low reproductive output for a large turtle, yet little is known about depredation of M. temminckii nests. We constructed 90 artficial M. temminckii nests in 2008 and 2009 at Black Bayou Lake National Wildlife Refuge in Louisiana to identify nest predators and elucidate patterns of nest depredation. All artficial nests were depredated, with Procyon lotor (Raccoon), and Dasypus novemcinctus (Nine-banded Armadillo) being the two most common nest predators. Other predators included Lontra canadensis (Northern River Otter), Didelphis virginiana (Virginia Opossum), and Lynx rufus (Bobcat). Nest depredation is a major threat to Alligator Snapping Turtles at this site and may be limiting recruitment in this population. [ABSTRACT FROM AUTHOR]

Six sites that were sampled for alligator snapping turtles in 1993-1994 were resampled in 2009 at the same locations where previous researchers trapped. Significantly fewer alligator snapping turtles were captured per trap night at all 6 sites, and the population structure of the alligator snapping turtles had a significantly different distribution in 2009 compared with 1993-1994. In order to continue monitoring their long-term trends in relative abundance and population structure, future sampling of alligator snapping turtles at these 6 sites is recommended. [ABSTRACT FROM AUTHOR]

Following perturbations like commercial harvests, turtles are susceptible to population declines because of life history characteristics such as long generation times, low recruitment rates, delayed maturity, and slow growth rates. Prior to gaining state-wide protection in 1993, the Alligator Snapping Turtle (Macrochelys temminckii) was commercially harvested in Arkansas. We conducted a mark-recapture study from 2005-2007 on a population of M. temminckii known to have been harvested in the East Fork Cadron Creek, a slow-moving stream in central Arkansas and part of the Mississippi River drainage. Captured turtles were marked, measured, weighed, and sexed. We compared observed characteristics to what would be expected if this population did not exhibit any evidence of past commercial harvest. We caught few large adults and approximately one adult for every juvenile. The adult sex ratio was highly female biased (6 F:1 M). Population density (18 turtles/km stream reach) was slightly lower than expected. The apparent survivorship for males (0.96), females (0.88), and juveniles (0.80) appear to be as expected for a large freshwater turtle. Whereas high survivorship rates may ameliorate the effects of historical commercial harvest, slow growth rates, low reproductive success, and long generation times have assured these effects to be long lasting and still present within our study population. We also suggest that there are factors impeding recovery of this population, such as life history characteristics and incidental catch by fisherman. [ABSTRACT FROM AUTHOR]

This study addresses habitat differences of two sympatric turtle species, alligator snapping turtles (Macrochelys temminckii) and eastern snapping turtles (Chelydra serpentina) in six watersheds in southeastern Missouri. We found that alligator snapping turtle presence corresponded with higher abundance of submerged physical structures in the stream, deeper water, relatively higher levels of detritus, and warmer water temperatures. Greater amount of aquatic vegetation was important in characterizing eastern snapping turtle presence in traps. Eastern snapping turtles and alligator snapping turtles did not use the same areas spatially at either a microhabitat or macrohabitat scale, and were only trapped at the same location once in 282 trap locations. Future conservation plans for the alligator snapping turtle and eastern snapping turtle should consider the microhabitat characteristics of sites used by these turtles. [ABSTRACT FROM AUTHOR]

We measured temperature-induced differences in metabolic rates and growth by embryos of three turtle species, Macrochelys temminckii, Trachemys scripta, and Apalone spinifera, at different, constant, temperatures. Oxygen consumption rate (VO2) was measured during development and used to characterize changes in metabolism and calculate total O2 consumption. Results from eggs incubated at different temperatures were used to calculate Q10s at different stages of development and to look for evidence of metabolic compensation. Total O2 consumption over the course of incubation was lowest at high incubation temperatures, and late-term metabolic rate Q10s were <2 in all three species. Both results were consistent with positive metabolic compensation. However, incubation temperature effects on egg mass-corrected hatchling size varied among species. Apalone spinifera hatchling mass was unaffected by temperature, whereas T. scripta mass was greatest at high temperatures and M. temminckii mass was lowest at high temperatures. Hatchling mass : length relationships tended to correlate negatively with temperature in all three species. Although we cannot reject positive metabolic compensation as a contributor to the observed VO2 patterns, there is precedence for drawing the more parsimonious conclusion that differences in yolk-free size alone produced the observed incubation temperature differences without energetic canalization by temperature acclimation during incubation. [ABSTRACT FROM AUTHOR]

Habersack, Mathew J., Theo A. Dillaha, and Charles Hagedorn, 2011. Common Snapping Turtles ( Chelydra serpentina) as a Source of Fecal Indicator Bacteria in Freshwater Systems. Journal of the American Water Resources Association (JAWRA) 47(6):1255-1260. DOI: 10.1111/j.1752-1688.2011.00572.x Abstract: The United States Total Maximum Daily Load program is required by Section 303(d) of the Clean Water Act to clean up waters that do not meet state water quality standards. While conducting research into the bacterial composition of semiaquatic mammal feces, the opportunity presented itself to quantify commonly used pathogen indicator bacteria in the gastrointestinal contents from an ectothermic (cold-blooded) animal, the common snapping turtle. Indicator bacteria concentrations were on the order of 106 CFU/g feces (dry weight basis). The estimated bacterial loadings from this study demonstrate that the common snapping turtle, if present in sufficient numbers, may contribute significant bacterial loadings to waterways and should be considered when developing bacterial Total Maximum Daily Loads and in other bacterial water quality assessments. [ABSTRACT FROM AUTHOR]

We report emergence dates for 38 alligator snapping turtle (Macrochelys temminckii) hatchlings from 6 naturally incubated nests laid during the 2008 and 2009 nesting seasons in northeastern Louisiana. Per capita emergence success for 2008 and 2009 combined was 19.5%. Hatchling emergence occurred from 28 August to 25 September and was asynchronous for 80% of nests that had multiple hatchlings emerge, with emergence duration as long as 12 days. We found no evidence of delayed emergence; some hatchlings may remain in the nest for up to 3 weeks before successfully emerging. [ABSTRACT FROM AUTHOR]

Seed dispersal by animals is well documented in many habitats; however, this knowledge is depauperate in bottomland hardwood forests. The alligator snapping turtle ( Macrochelys temminckii) is a large freshwater turtle of the southeastern United States that consumes primarily fish but also eats vegetation, including seeds of trees. To evaluate the role this species may play as a seed disperser in bottomland hardwood systems, we investigated the effect of ingestion by M. temminckii on germination of seeds of the following trees: common persimmon ( Diospyros virginiana), water tupelo ( Nyssa aquatica), and willow oak ( Quercus phellos). Captive turtles were presented seeds of these three species in a series of feeding trials. Ingestion reduced the proportion of seeds that germinated compared to uneaten controls for D. virginiana and N. aquatica but had the opposite effect on Q. phellos. Ingested D. virginiana and N. aquatica seeds also germinated more slowly than uneaten controls; however, ingested Q. phellos seeds germinated faster than uneaten controls. This study suggests M. temminckii may have a role as a disperser of Q. phellos, N. aquatica, and D. virginiana; however, information on post-dispersal seed fate is needed to completely assess this species and other freshwater turtles as dispersers of wetland vegetation. [ABSTRACT FROM AUTHOR]

Abstract: Ectotherms in water experience rates of heat transfer at least two orders of magnitude greater than in air, seriously constraining their thermoregulatory capabilities. Yet, even in water, individuals may exert control over body temperature (T b ) via behaviors such as selecting thermally favorable microhabitats. The interactions among body size, physiology, and behavior on the thermal biology of large, entirely aquatic, ectotherms is poorly understood. We tested the hypothesis that alligator snapping turtles (Macroclemmys temminckii) selected microhabitats based on temperature by comparing temperatures at sites used by turtles to temperatures at randomly selected sites. These large turtles selected a narrow range of microhabitats that were significantly warmer and less variable in temperature than random sites. Cooling trials in the laboratory indicated larger turtles equilibrated more slowly to ambient temperature (T a ) than smaller turtles. We recorded T a and body temperature (T b ) of turtles in the field continuously throughout the year. The T b generally conformed to T a but there were periods when T b −T a differences were great. These results suggest that while physiology and size of aquatic turtles can affect T b transiently, microhabitat selection may be the only meaningful mechanism for large, entirely aquatic, turtles to control T b . [Copyright &y& Elsevier]

We conducted a mark-recapture study of the turtle assemblage inhabiting a 1.1 km reach of the Santa Fe River within River Rise Preserve State Park in northern Florida during drought conditions in 2006 and 2007. In 154 man-hours of snorkeling, we hand-captured eight species, including two Florida listed Species of Special Concern -- the Suwannee Cooter (Pseudemys concinna) and Alligator Snapping Turtle (Macrochelys temminckii). Species diversity (Shannon H') and species evenness (Pielou J') were 1.23 and 0.59, respectively. The most abundant species was P. concinna, comprising 54.5% of all individuals captured and 77.9% of the total assemblage biomass. Biomass of the entire assemblage was estimated to be 199.8 kg/ha. This is the first detailed description of a turtle assemblage occurring in a blackwater stream habitat in the southeastern United States. [ABSTRACT FROM AUTHOR]

Moll's (1988) report to the Illinois Endangered Species Protection Board recommended attempts to locate viable populations of alligator snapping turtles (Macrochelys temminckii) before considering management actions. We surveyed 18 sites in southern Illinois and captured 2,671 turtles, none of which were M. temminckii. No verifiable records were obtained from our solicitation of observations in two regulatory publications of the Illinois Department of Natural Resources. Our findings are supported by other chelonian studies and a lack of documented records of M. temminckii in Illinois during the past quarter century. We conclude recovery of this species is unlikely in Illinois without direct management such as translocation or release of captive-raised individuals. [ABSTRACT FROM AUTHOR]

Translocation is often considered a viable conservation strategy, despite the absence of species-specific post-translocation data. Macrochelys temminckii (Alligator Snapping Turtle) populations have declined across their range and they may be considered candidates for translocation, but few studies have examined the response of individuals to movement events. I monitored M. temminckii with radiotelemetry in northwest Louisiana to provide baseline data regarding the species' response to translocation. I calculated average distances moved per day, measured water depths, and recorded growth of translocated and resident turtles. There was no observed mortality during the study, and translocated turtles gained mass and increased shell dimensions, indicating they effectively located resources after translocation. Resident individual shell dimensions increased, but some residents lost mass, possibly due to early recapture and reweighing dates. Movement distances were within the ranges reported by previous researchers. These data contribute baseline information concerning M. temminckii conservation biology. [ABSTRACT FROM AUTHOR]

Habitat selection in adult Alligator Snapping Turtles (Macrochelys temminckii) is known for only a few populations. Given that habitat availability can vary in different geographical locations, we used radiotelemetry to study habitat selection in a riverine habitat in central Arkansas by attaching radio transmitters to 14 female and four male Alligator Snapping Turtles. We tested the hypothesis that males and females select different habitats throughout the year because of differences in reproductive cycles and higher thermoregulatory requirements for females prior to nesting. Our results indicated that males and females selected similar habitats with similar thermal properties, but both sexes selected submerged structure. The tendency for Alligator Snapping Turtles to select sites with structure may be caused by higher prey densities (e.g., fish and crayfish) in these areas, protection from predators (e.g., American Alligators), or as an aid in surfacing to breathe rather than for thermoregulatory purposes. [ABSTRACT FROM AUTHOR]

Alligator snapping turtle (Macrochelys temminckii) populations have declined across much of the southeastern United States in recent decades, due at least in part to overcollection. Recently, however, legal protection from large-scale harvesting has been granted to the species in all states where it is native, thereby drastically reducing one of the greatest threats to its survival. There is growing interest in captive propagation of alligator snapping turtles for reintroduction where populations have been decimated. In conjunction with one such effort, we analyzed the physiological effects of temperature on embryonic and posthatching development. Results indicate that extreme high and low incubation temperatures negatively affected embryo survival, and high incubation temperatures corresponded with shorter incubation time but also produced smaller hatchlings. The effects of temperature on gonadal differentiation indicated that the upper pivotal temperature was approximately 27.5°C. Posthatching growth was faster at warmer water temperatures, and there was little to no acclimation of metabolic rate to exposure to either incubation or water temperature. We conclude that intermediate (27.5°-28.5°C) incubation temperatures produce a female-biased mixed sex ratio and maximize hatching success and hatchling size while increasing incubation duration only slightly over that at the higher temperatures. In addition, posthatching growth was positively influenced by hatchling body temperature; therefore, warmer water temperatures (∼30°C) decreased the time required to rear turtles to a size suitable for reintroduction. [ABSTRACT FROM AUTHOR]

Haemogregarina macrochelysi n. sp. (Apicomplexa: Haemogregarinidae) of the alligator snapping turtle, Macrochelys temminckii, is characterized by slender, recurved gamonts 29-35 × 3-4.5 μm, in which the anterior limb comprises 48-54% of the total length. The gamont nucleus, 5-7.5 × 2-5 μm, is situated at approximately midbody of the gamont. Meronts typical of Haemogregarina occupying erythrocytes have 3-8 small, compact nuclei and are 13-17 × 4.5-9 μm. Erythrocytic meronts that contain larger, nearly square or rectangular nuclei become rounded, and then undergo 7 or more nuclear divisions, which produce very large, usually ovoid to rounded meronts that may contain up to 150 nuclei or more within the thinly stretched host erythrocyte membrane. In tissues of the Placobdella spp. leech vectors, merogony occurs directly from sporozoites, forming merozoites that presumably are infective for the turtle host. [ABSTRACT FROM AUTHOR]